1. Field of the Invention
The invention relates to a tube consisting of plastic or metal and having a neck sealed by a membrane and covered by a cap having a punch member for piercing the membrane.
2. Description of the Prior Art
The neck openings of tubes, particularly tubes containing medication, are usually sealed by membranes in order to prevent contamination of the content of such tubes. In this manner, the tube content can be stored over a relatively long period of time even if the content is easily perishable once exposed to air. Also medication can remain sterile until the tube is opened.
The tube is normally opened by means of a punch which is disposed in the screw cap and with which the membrane is pierced and pushed into the interior of the tube. Usually, the punch is provided inside on top of the cap and the cap is firmly threaded onto the tube neck in order to prevent the sensitive membrane from being damaged by mechanical objects. It is, however, also possible to arrange the punch member within the screw cap, but then means must be provided for preventing unwanted piercing of the membrane upon mounting of the screw cap onto the tube neck.
With all these arrangements, the membrane, when pierced, is pushed into the tube. This however is disadvantageous since parts of the ruptured membrane will emerge from the tube with the content or, at least, they will return to their original position, thereby restricting or impeding the flow of the content from the tube and resulting in inconveniences. It is therefore the principal object of the present invention to provide a tube whose neck is closed by a membrane in the manner known as reliable but which can be opened without the membrane being forced into the tube.